Synthesis Of Heterocyclic Compounds Catalyzed By Poly(2-acrylamido-2-methylpropanesulfonic Acid)

Poly(2-acrylamido-2-methylpropanesulfonic acid)(PAMPS)was prepared by free radical polymerization using 2-acrylamido-2-methylpropanesulfonic acid as monomer and N,N'-methylenebisacrylamide as cross-linker.H+density and sulfur element content of PAMPS were determined.?-Indolylketones were synthesized by the Michael addition reaction of indole and benzylideneacetophenone in ethanol solvent using PAMPS as heterogeneous catalyst.The influence of PAMPS degree of crosslinking,particle size,amount on the catalytic effect was studied.The reaction is simple and easy to operate.The catalyst is inexpensive,environmentally friendly and recyclable.The yields of?-Indolylketones were 67%to 93%.H+ionized from PAMPS acted as catalyst.PAMPS was used as both catalyst and water absorbent for acetalization.The sulfur element content of PAMPS was determined by oxygen-flask combustion method.The H+density was determined by titration.The contents of free water and bound water absorbed by superabsorbent PAMPS were determined by differential scanning calorimetry.Acetal by the reaction of aldehyde and diol without solvent was synthesized using PAMPS as both catalyst and water absorbent.Compared with traditional method,toluene was not used to remove water by azeotropy in the reaction.Compared with traditional catalyst ion exchange resin,the dose of PAMPS was less,but the catalytic effect of PAMPS was better.It was easily to separate PAMPS from reaction mixtures,PAMPS was recyclable.The contents of aldehyde,diol and acetal absorbed by PAMPS in the reaction were determined by gas chromatography.Water absorbed by PAMPS in the reaction was determined by Karl Fischer reagent.The amounts of diol and water absorbed by PAMPS were large,the amounts of aldehyde and acetal absorbed by PAMPS were less.The larger the ratio of water absorbed by PAMPS to water unabsorbed by PAMPS,the higher the yield of acetal.Poly(ferric 2-acrylamido-2-methylpropanesulfonate)(PFAMPS)was prepared by the reaction of PAMPS and Fe(OH)3.PFAMPS was used as catalyst for Biginelli reaction of aromatic aldehyde,ethyl acetoacetate and urea(sulfourea)to synthesize 3,4-Dihydropyrimidinones.The catalytic effect of PFAMPS,ferric cellulose sulfonate,ferric starch sulfonate,ferric lignosulfonate and ferric 732 cation exchange resin was studied,the catalytic effect of PFAMPS was the best among those catalysts.The Fe3+content of PFAMPS was determined by back titration.PFAMPS was easy to separate from the reaction mixtures,PFAMPS could be reused and the catalytic effect of recycled PFAMPS decreased little.The yields of 3,4-dihydropyrimidone were 70%to 86%.The structure of product was determined by 1H NMR.